Molecular effects of hesperetin, a citrus flavanone on7,12-dimethylbenz(a)anthracene induced buccal pouch squamous cell carcinoma in golden Syrian hamsters.

In recent years, researchers have been focused on citrus flavanone, a naturally occurring bioactive substance of hesperetin. To investigate the molecular mechanism based chemopreventive efficacy of hesperetin on 7,12-dimethylbenz(a)anthracene (DMBA) induced hamster buccal pouch (HBP) squamous cell carcinoma (SCC). The oral tumour was provoked by painted with 0.5% DMBA on left buccal pouch thrice a week for 10 consecutive weeks developed well-differentiated SCC and tumour formation was 100% in DMBA alone. We evaluated the chemopreventive potential of hesperetin by assessing the lipid peroxidation (LPO) by-products, status of enzymatic, non-enzymatic antioxidants, detoxifying agents etc. Moreover, modulating expression of apoptotic and cell proliferation markers were observed in HBP SCC experimental hamsters. Oral administration of hesperetin (20 mg/kg b.w.) to DMBA painted hamsters significantly reversed the stages of oral SCC. Our findings indicate that hesperetin possesses a chemopreventive effect in DMBA-induced oral SCC by exerting anti-carcinogenic property.

Estimation of age using aspartic acid racemisation in human dentin in Indian population.

AIM: The quest to identify an accurate method of age estimation, had lead to the evaluation of aspartic acid racemisation in hard tissues of the human remains using high performance liquid chromatography (HPLC). Our study is aimed at the applicability of the racemisation technique to use dentin as the sample to estimate the age in South Indian sub-population. MATERIALS AND METHODS: Thirty-six non-carious teeth from living individuals distributed among 6 age groups (6 each), sexes (18 each) and jaws (18 each) were analysed for dextro (d) and levo (l) forms of aspartic acid using high performance liquid chromatography (HPLC) technique and their racemisation ratio were calculated for each tooth sample. RESULTS: High correlation was obtained between the aspartic acid racemisation rates in dentin and age of the individual with an error limited to ±3 years. Racemisation rates in teeth did not significantly differ between the sexes or jaws. CONCLUSION: The d-aspartic acid accumulation in dentin is synchronous with the aging of an individual and can be used as an accurate method of age estimation in our population.

Geraniol modulates cell proliferation, apoptosis, inflammation, and angiogenesis during 7,12-dimethylbenz[a]anthracene-induced hamster buccal pouch carcinogenesis.

Oral carcinogenesis, a multistep process with multifaceted etiology, arises due to accumulation of heterogeneous genetic changes in the genes involved in the basic cellular functions including cell division, differentiation, and cell death. These genetic changes in the affected cell progressively increase the cell proliferation, angiogenesis, and inhibition of apoptosis. The present study investigated the modulating effect of geraniol on the expression pattern of cell proliferative (PCNA, cyclin D1, c-fos), inflammatory (NF-κB, COX-2), apoptotic (p53, Bax, Bcl-2, caspase-3 and -9), and angiogenic (VEGF) markers in 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. Topical application of 0.5 % DMBA in liquid paraffin, three times a week, for 14 weeks, developed well-differentiated squamous cell carcinoma (SCC) in the buccal pouch of golden Syrian hamsters. All the hamsters treated with DMBA alone (100 %) developed oral tumors in the buccal pouch after 14 weeks. Over-expression of mutant p53, PCNA, Bcl-2, and VEGF accompanied by decreased expression of Bax were noticed in hamsters treated with DMBA alone. Increased expression of c-fos, COX-2, NF-κB, and cyclin D1 and decreased activities of caspase-3 and -9 were also noticed in hamsters treated with DMBA alone. Oral administration of geraniol at a dose of 250 mg/kg bw (body weight) not only completely prevented the formation of oral tumors but also prevented the deregulation in the expression of above mentioned molecular markers in hamsters treated with DMBA. The present results thus suggest that geraniol has potent anti-inflammatory, anti-angiogenic, anti-cell proliferative, and apoptosis-inducing properties in DMBA-induced hamster buccal pouch carcinogenesis.

Role of receptors of advanced glycation end-products (RAGE) in type 2 diabetic and non-diabetic individuals with chronic periodontal disease: an immunohistochemical study.

AIM: The relationship between diabetes and periodontal disease is well established. It has been shown that advanced glycation end-products might exert noxious effects on several tissues of the body through its receptor. Evidence for the role of receptors of advanced glycation end-products in periodontal disease for diabetes is limited, and their presence in human gingival tissues has been demonstrated in few studies. In this study, we demonstrate the presence of receptors of advanced glycation end-products in patients with chronic periodontitis, with and without type 2 diabetes. METHODS: Gingival biopsies from 19 patients with both type 2 diabetes and chronic periodontitis, and 18 healthy controls with chronic periodontitis, were immunohistochemically stained for receptors of advanced glycation end-products. RESULTS: On immunohistochemical analysis, positive staining for receptors of advanced glycation end-products was seen in the endothelium and the basal and spinous layers of the inflamed gingival epithelium in both type 2 diabetes and non-diabetes tissue, with a statistically-significant difference between both groups (P <0 .05). CONCLUSIONS: There was a significant difference in receptors of advanced glycation end-product immune reactivity between both groups. Receptors of advanced glycation end-product increase in type 2 diabetes gingival tissue might indicate possible involvement of this receptor in periodontal destruction in individuals with type 2 diabetes.

Protective effect of berberine on expression pattern of apoptotic, cell proliferative, inflammatory and angiogenic markers during 7,12-dimethylbenz(a)anthracene induced hamster buccal pouch carcinogenesis.

Investigation of expression pattern of molecular markers in oral epithelial tissues would help to assess the cell differentiation and proliferation as well as early diagnosis of precancerous and cancerous lesions of the oral cavity. Aim of the present study was to investigate the protective effect of berberine on expression pattern of apoptotic, cell proliferative, inflammatory and angiogenic markers during 7,12-dimethylbenz(a)anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Immunohistochemical staining [p53, Bcl-2, Bax, Proliferating Cell Nuclear Antigen (PCNA) and Vascular Endothelial Growth Factor (VEGF)], Enzyme Linked Immuno Sorbent Assay (ELISA) [c-fos, COX-2, caspase-3 and -9] and Real-Time PCR [Cyclin D1 and NFkappaB] were utilized to assess the expression pattern of molecular markers in DMBA induced hamster buccal pouch carcinogenesis. Over expression of mutant p53, PCNA, Bcl-2 and VEGF were noticed in hamsters treated with DMBA alone. Decreased expression of Bax protein was noticed in hamsters treated with DMBA alone. Increased expression of C-fos, COX-2, NFkappaB and Cyclin D1 and decreased activities of caspase-3 and -9 were also noticed in hamsters treated with DMBA alone. Oral administration ofberberine at a dose of 75 mg kg(-1) b.w. brought back the expression of above mentioned molecular markers to near normal pattern in hamsters treated with DMBA. The present results thus suggest that berberine has potent anti-inflammatory, anti-angiogenic, anti-cell proliferative and apoptosis inducing properties in DMBA induced oral carcinogenesis.

Antigenotoxic effect of genistein against 7,12-dimethylbenz[a]anthracene induced genotoxicity in bone marrow cells of female Wistar rats.

Carcinogen induced mutation in somatic cells leads to genetic instability, which is considered as an important facet of carcinogenesis. Agents that inhibit DNA adduct formation, stimulate DNA repair mechanisms, and possess antioxidant functions are considered as antigenotoxic agents. Genistein, the major isoflavone of soy products, protects animals against experimentally induced mammary and prostate cancers. 7,12-Dimethylbenz[a]anthracene (DMBA), a potent site-specific carcinogen, induce mutations in DNA through its active metabolite, dihydrodiol epoxide, what is a crucial step in cancer initiation. The antigenotoxic effect of genistein against DMBA-induced genotoxicity has been investigated in the present study by analyzing the frequency of micronucleated polychromatic erythrocytes (MnPCEs) and chromosomal aberrations as cytogenetic end-points. The status of lipid peroxidation, antioxidants and detoxication agents were used as biochemical end-points to assess the antigenotoxic effect of genistein. Elevated MnPCEs frequency, marked chromosomal aberrations and enhanced status of lipid peroxidation, antioxidants and detoxication agents were observed in DMBA-treated animals. Oral pretreatment of genistein (20 mg/kg b.w.) for 5 days to DMBA-treated animals significantly reduced the frequency of micronucleus formation and chromosomal abnormalities as well as reversed the status of biochemical variables. Our results suggest that genistein has potent antigenotoxic effect against DMBA-induced genotoxicity.

Protective role of Withaferin-A on immunoexpression of p53 and bcl-2 in 7,12-dimethylbenz(a)anthracene-induced experimental oral carcinogenesis.

Oral cancer, the fifth most frequent cancer worldwide, is a major health problem and accounts for highest morbidity and mortality in human populations. This form of cancer accounts for 40-50% of all cancers in developing countries including India. Despite recent advancement in the treatment, imaging and diagnosis of oral carcinoma, a 5-year survival and mortality rate for this cancer is still at 50%. Our aim was to study the protective effect of Withaferin-A on molecular pathogenesis of oral cancer by evaluating the immunoexpression of p53 and bcl-2 proteins. Oral squamous cell carcinoma was developed in the left buccal pouch of golden Syrian hamsters by painting with 0.5% 7,12-dimethylbenz(a)anthracene (DMBA), three times a week for 14 weeks. We observed 100% tumor formation with high tumor volume and burden in the DMBA alone painted hamsters as compared to control hamsters. We also observed markedly altered expression of p53 and bcl-2 proteins in tumor tissues of oral cancer bearing hamsters. Oral administration of Withaferin-A to DMBA-painted hamsters not only completely prevented oral squamous cell carcinoma formation but also significantly prevented the alterations of p53 and bcl-2 expressions. Our results thus suggest that Withaferin-A has significant protective role against DMBA induced molecular alterations in the buccal mucosa of golden Syrian hamsters.

Protective role of withaferin-A on 7,12-dimethylbenz(a)anthracene-induced genotoxicity in bone marrow of Syrian golden hamsters.

The present study has investigated the antigenotoxic effect of withaferin-A, a steroidal lactone obtained from the roots and leaves of Withania somnifera, in 7,12-dimethylbenz(a)anthracene (DMBA)-induced genotoxicity. Measurement of the frequency of micronucleated polychromatic erythrocytes (MnPCEs) and chromosomal aberrations is used as cytogenetic endpoints. A single intraperitoneal injection of DMBA (30 mg/kg b.w.) to golden Syrian hamsters resulted in marked elevation in the frequency of MnPCEs and aberrations in the chromosomal structure. Hamsters pretreated with withaferin-A intraperitonealy 2 h before the injection of DMBA, significantly reduced the frequency of MnPCEs and chromosomal aberrations such as chromosomal break, gap, minute, and fragment. Our results thus demonstrated the antigenotoxic effect of withaferin-A in DMBA-induced genotoxicity in the bone marrow of golden Syrian hamsters.

Protective effect of Withaferin-A on micronucleus frequency and detoxication agents during experimental oral carcinogenesis.

Our aim was to investigate the effect of Withaferin-A on bone marrow micronucleus frequency and buccal mucosa detoxication agents during 7, 12-dimethylbenz[a]anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Oral squamous cell carcinoma was developed in hamsters' buccal pouches by painting 0.5% DMBA in liquid paraffin, three times per week for 14 weeks. We observed 100% tumor formation in DMBA painted hamsters. Elevated frequency of bone marrow micronucleated polychromatic erythrocytes (MnPCEs) and decrease in buccal mucosa phase II detoxication agents were noticed in tumor bearing hamsters. Oral administration of Withaferin-A significantly reduced the micronucleus frequency and brought back the status of phase II detoxication agents in DMBA painted hamsters. Our study thus demonstrated the protective effect of Withaferin-A on DMBA-induced micronucleus frequency in the bone marrow of golden Syrian hamsters. Also, Withaferin-A maintained the status of buccal mucosa detoxication agents during DMBA-induced hamster buccal pouch carcinogenesis.